Avaliou-se a recuperação de oocistos de Cryptosporidium spp. em amostras de água e leite. As amostras foram contaminadas experimentalmente com uma suspensão de 1,2×10(7) oocistos de Cryptosporidium spp. e concentradas por centrífugo-flutuação para comparação entre diferentes substâncias (sacarose, NaCl, MgSO4, ZnSO4, AlSO4, NH4SO4 40% e NH4SO4 80%). A centrifugação das amostras foi realizada em duas etapas para concentração utilizando-se dois métodos, diferentes pela ordem do uso das soluções saturadas no procedimento, na primeira etapa de concentração do método I, e na segunda etapa, do método II. A identificação do oocisto foi realizada mediante as técnicas de coloração histoquímica Kinyoun e Koster modificado. O grau de recuperação de oocistos foi 10,9% com NaCl e 42,5% com MgSO4 nas amostras de água e leite, respectivamente (método I), e de 10,6% com NaCl e 5,3% com sacarose nas amostras de água e leite, respectivamente (método II). Os métodos de coloração histoquímica não influenciaram nos resultados. A eficácia dos métodos de recuperação de oocistos de Cryptosporidium spp. depende da natureza e composição da amostra e da metodologia usada para a concentração dos oocistos na amostra.

Cryptosporidium spp. oocyst recovery in water and milk samples was evaluated. Samples were inoculated with a suspension of 1.2×10(7) Cryptosporidium spp. oocysts and submitted to centrifugal flotation, using different solutions (sucrose, NaCl, MgSO4, ZnSO4, AlSO4, NH4SO4 40% and NH4SO4 80%). Centrifugation of the samples was carried out in two stages for concentration using two methods that differed in the order in which the saturated solutions were used, namely only in the first stage of method I and only in the second stage of method II. Oocyst identification was performed using the Kinyoun and Koster histochemical staining techniques. Samples analyzed by method I showed different degree of oocyst recovery, namely 10.9% with NaCl and 42.5% with MgSO4 in water and milk samples, while those samples analyzed by method II showed 10.6% with NaCl and 5.3% with sucrose in water and milk, respectively. Histochemical staining methods have no influence on the degree of oocysts recovery. The efficiency of Cryptosporidium spp. oocysts recovery methods depends on the nature and composition of the sample and on the methodology used for oocyst concentration.

The potential production of rhamnolipid-type biosurfactants is assessed based on the development of a fermentative process with a strain of Pseudomonas aeruginosa PA1, which was isolated from oil production wastewater in the Northeast of Brazil. These production of molecules using different carbon (n-hexadecane, paraffinic oil, glycerol and babassu oil) and nitrogen sources (NaNO3, (NH4)2SO4 and CH4N2O) was studied. The best results were obtained when using glycerol as substrate. A C/N ratio of 60/1 and use of sodium nitrate as nitrogen source resulted in higher production of the rhamnolipid, expressed by rhamnose (3.16 g/L) and by the yield in relation to biomass (Yp/x = 0.70 g/g). Additionally, physical-chemical characteristics of the spent broth with and without cells were studied, providing a low critical micelle concentration of 19 mg/L and toxicity values of 13 and 13.8 mg/L using two test organisms, the micro crustacean Daphnia similis and the bacterium Vibrio fisheri (Microtox), respectively.

In this work a hybrid neural modelling methodology, which combines mass balance equations with functional link networks (FLNs), used to represent kinetic rates, is developed for bioprocesses. The simple structure of the FLNs allows the easy and rapid estimation of network weights and, consequently, the use of the hybrid model in an adaptive form. As the proposed model is able to adjust to kinetic and environmental changes, it is suitable for use in the development of optimization strategies for fed-batch bioreactors. The proposed methodology is used to model the processes for penicillin and ethanol production, and the development of an adaptive optimal control scheme is discussed using ethanol fermentation as an example.